Test kit in, CYA too high

[IslandChad]

Just got my Taylor k2006 kit in.

Ran CYA test first and it’s off the charts, well over 100. The water line is right over the CYA label so maybe 150ish?

My water is clear and looks great. I don’t really want to drain half my water either. I’m on rural water and filling it is so very slow.

What do do I need to do? Will it cost me way more in chlorine to keep the CYA this high?

thanks.

 

[Texas Splash]

Yes, the problem with such a high CYA is trying to keep the FC high enough to compensate. It will also be so high that you'll never be able to get an accurate pH reading either because it will in-turn record as high. To be sure how high it is, you should do a diluted test as noted on the TFP Pool School - CYA page starting at step #8. That way you know for sure if it's 150 or more like 200.... or maybe a little less?

If it does turn out to be over 100, I wouldn't take a chance, I'd exchange some water. The sun is cranking-up, so you could get by with a CYA of 70 if you had to in a non-SWG pool, but anything too much higher is a ticking time bomb. I know it's a shame because your water does look nice, but that's my recommendation. Do what you need to on your end, keep an eye on things or let us know if you have any other questions.

 

[IslandChad]

I did the modified test and that was still above 100 so that means I’m over 200 CYA. The test strips I had suck. They always said I was low.

How much water would would I need to change out? Half? A quarter a few times?

 

[Texas Splash]

How much water would would I need to change out?

Wow! You really were getting up there. Well, in simple terms .... exchange half the water get half the CYA. So with a CYA of 200, you change half and should get a new CYA of about 100. Start with a CYA of 100 and change half to get a CYA of 50. With a vinyl above ground, you don't want to lower anymore than about 12-18 inches to keep the pool stable. Do a process that works best for you in an effort to get the CYA under 100, preferably at 70 or less, and you'll find the water much better to manage.

 

[Richard320]

Been there, done that.

If it's not completely verboten, replace water. I couldn't, and I was terrified of getting algae. Also, I had to run such high FC that I was never certain of my pH readings. The actual FC losses won't be significantly different whether CYA is at 50 or at 200; the high CYA reduces the losses, but the high FC increases them. In my experience, I use the same every day now as I did a few years ago. The reason I'm telling you this is that if you end up after a couple drains at 70 CYA, you could stop there and let it go down further through splashout and backwashing and normal breakdown. Just be aware that the higher the CYA, the higher the shock level, so take great pains to not get algae!

 

[IslandChad]

Thanks everyone for the advice.
I drained a bit yesterday and refilled. Retested with a diluted CYA test (I did 1/3 pool water, 2/3 tap) and it read as 50, so 50 x 3=150 CYA, which is good as I was over 200. I will repeat this a few more times.

PH is perfect at 7.6
The FC and CC tests confused me a bit. Add powder, add more powder if water is not pink... it confused me a little bit.

 

[Texas Splash]

The FC and CC tests confused me a bit. Add powder, add more powder if water is not pink... it confused me a little bit.

I explain it this way:

10 ML water sample with one hefty scoop of R-0870 power & mix (should turn Barbie pink to indicate chlorine). If it didn't turn pink, then you have zero or next to no free chlorine in the pool. Mix and add R-0871 drops, counting until clear. Once clear, take that number and divide by 2. Example: 20 drops = FC of 10.

 

[Casey]

You are doing yourself and the water a great service by getting the CYA down. You have a beautiful pool and deck with clear blue water. Let's keep it that way. You'll love the test kit.

 

[IslandChad]

Replaced more water this weekend and got CYA to about 120 (I only had to do a half pool water / half tap water modification). Down from over 200 so definitely making progress. I will keep replacing water about once a week, I just can't do it every day. I am still working on getting FC/CC numbers to look right as well.

I am going to pick up a bunch of 10% chlorine today and test tonight.
With my CYA still very high, what should I be trying to get my FC to be?
And I never did an official slam. My water is really clear still, so I am not sure when/if I need to slam.

Thanks for your continued help. I feel like I am starting to get the hang of this but I still have a lot to learn.

 

[Texas Splash]

With my CYA still very high, what should I be trying to get my FC to be?

We know a CYA of 100 requires a daily range about 11-13 and never below 8. At your current CYA of 120, bump that up a bit and I'd say you want to keep the FC in the 13-15 range, never below 10. Of course you know that's a tough area to be in, but you're working the water exchanges as best as you can. That's understood. Hopefully things will stay clear for you as you keep moving ahead. Good luck!

 

[IslandChad]

OK... I overshot a FC of 13-15 and hit 20. Is that too high to get in now and still be safe?
I know my kids want to swim. I will test it again today. I am sure it dropped some with the sun shining all over the pool today.
Just curious what the cutoff point is...

Thanks

 

[Texas Splash]

OK... I overshot a FC of 13-15 and hit 20. Is that too high to get in now and still be safe?

With that high CYA you currently have, it's just fine.